I have WinSCP version 5.1.3 (build 2881) installed on Windows7 x86. Any SFTP connection on my WinSCP install has been protect with master password and I have detect a problem when execute this steps:
1. set in preference a master password for any SFTP connection saved
2. create a SFTP connection and save it with a specific name form domain
3. close and reopen WinSCP
4. select a SFTP connection creted at step2
5. click on modify
6. winSCP ask me the master password to enabling the modify the SFTP connection. But in this case, if push a ESC button on my keyboard, WinSCP enable my action to modify though I do not know the master password.